Barack Obama ran as a hope-and-change candidate who was going to forget about red states and blue states and have us all singing "kumbaya" together on some make-believe hilltop in the Land of Post-Partisanship. Those dreams are long since dashed — as the president's critics on both sides acknowledge. But we got yet another reminder about the president's inability to bridge partisan divides this week, when White House press secretary Josh Ernest declared, "If this bill passes this Congress, the president wouldn't sign it."

He was referring to the Keystone XL pipeline.

This project has been mired in controversy and delay for years. But it actually has supporters on both sides of the aisle, including labor unions on the left and free-market conservatives on the right. It's largely just liberal environmentalists who are pressuring Democrats to hold things up.

But Obama's own State Department produced an environmental impact statement long ago green-lighting the project. "The central finding in the draft environmental impact statement," The New Yorker's Ryan Lizza told NPR's Terry Gross last year, "was, if you don't build Keystone, the Canadians will sell this stuff anyway, they'll build pipelines to their east coast, to their west coast, and they'll send it to the Gulf of Mexico via rail — and by the way, sending oil by rail releases a whole lot more greenhouse gas emissions than putting it in a pipeline."

And as TheNew York Times noted a year ago, "The department’s long-awaited environmental impact statement appears to indicate that the project could pass the criteria Mr. Obama set forth in a speech last summer [2013] when he said he would approve the 1,700-mile pipeline if it would not 'significantly exacerbate' the problem of greenhouse gas emissions."

But there are powerful and wealthy environmental interests lined up against Keystone. As Jim Antle notes, "Billionaire environmentalist Tom Steyer spent heavily trying to rally voters against the pipeline. He supported Democrats, especially anti-Keystone ones, in key Senate races. Despite assembling $85 million in funding, most of Steyer's candidates — four out of six, to be exact — lost."

Obama has the ability to rhetorically present both sides of every issue. But he also has a habit of ultimately coming down on the left side. He's a liberal at heart. But there's more to it than that. Obama fans are loathe to admit it, but the president can be a divider, and an obstructionist.

If Obama were really concerned about bridging the gap, he wouldn't reflexively promise to veto the first piece of legislation presented to him by this new Congress. Doing so doesn't exactly demonstrate that he heard the message voters sent him in November when, yes, his policies were on the ballot, and yes, they were rejected. But perhaps more importantly, passing Keystone would be a gesture of goodwill to a new Congress. It might actually restore some small modicum of hope in the American people that their government can get something done — that we aren't predestined to suffer gridlock and obstructionism. And heck, half his party already wants Keystone, anyway.

The irony is that, had Obama governed the way he campaigned, he might have changed the paradigm, reordered the political scene, and essentially broken the Republican Party. I'm hardly alone in thinking this. During a recent episode of Conversations with Bill Kristol," former Speaker Newt Gingrich echoed my sentiment:

I listened to Obama's first inaugural — which really built on his Grant Park speech on election night, and on his speech in Manassas in Virginia on the Saturday before the election. And Callista and I were at the Capitol for the inaugural, and I turned to her on the way out, and I said: "If he'll govern the way he just spoke, he'll be Eisenhower. He'll split the Republican Party, he'll dominate the country. And within six weeks, Pelosi and Reed had convinced him to go to the left, write totally partisan bills, close out the Republicans. And he just threw away the chance to be, sort of the great re-unifier. [Newt Gingrich]

It's not as simple as that, of course. The GOP wasn't exactly itching to compromise with Obama. But as much as liberals don't want to admit it, and want to blame all of Obama's failures on the GOP, he's the president. It's his job to lead. And, as this veto threat demonstrates, he's a real part of the problem in Washington.